The best reason for encouraging people to save even when young may be that it helps form habits they'll be glad of later, including the habit of not trying to live "without financial constraints" (because unfortunately those are always there and you don't gain anything by pretending otherwise).

Also, I think your calculation isn't the best one: you need to look at the age-28 gains from having saved $1000 per year for 10 years -- including the fact that the resulting money is there just as if you'd invested it afresh at age 28. It's not as if putting money into savings at age 28 is an alternative to doing it when younger: you can do both.